fix(kyberforge): trim forge description and body to ADR-0020 budgets

factory-audit flagged forge's description and body as over the ADR-0020
targets (250 chars / 600 words). The description now uses three boundary
clauses and the body is 595 words. The context: fork vs /fork gotcha moved
to references/author-routes.md, the only place the fork-or-inline choice
is made. No routing row or behaviour changed.

Fixes: #143

Co-Authored-By: Claude Code <[email protected]>
Claude-Session: https://claude.ai/code/session_01KkT7RSDwDbmrM9T34b6sTi

plugins/kyberforge/.apm/skills/forge/references/sources.md

@@ -12,8 +12,8 @@
 
 - **URL:** context7:/websites/code_claude
 - **Research doc:** plugins/kyberforge/docs/research/docs/claude-code-plugins/sources.md
-- **Description:** Official Claude Code documentation site indexed by Context7 — confirms the `context: fork` skill-level frontmatter field means isolated/fresh execution, the opposite of what the `/fork` subagent command does (inherits conversation). Informs the Gotchas entry in `SKILL.md` warning against conflating the two; nothing else in this skill draws on it, and no `references/` file mentions the `context: fork` field.
-- **Contributing files:** SKILL.md
+- **Description:** Official Claude Code documentation site indexed by Context7 — confirms the `context: fork` skill-level frontmatter field means isolated/fresh execution, the opposite of what the `/fork` subagent command does (inherits conversation). Informs the `context: fork` gotcha in `references/author-routes.md` warning against conflating the two; nothing else in this skill draws on it.
+- **Contributing files:** references/author-routes.md
 - **Status:** `extracted`
 
 ## claude-code-plugins-docs